The object of the invention is a mat for a hybrid turf, comprising artificial grass and facilitating growth of natural grass.
Turfs are basically classified as natural turfs and artificial turfs. Natural turfs, wherein grass grows directly on soil, provide high comfort of use, but are prone to damage under heavy use. A damaged natural turf needs long time to recover. Artificial turfs, which consist solely of synthetic material, usually have a form of an artificial mat, from which long blades of artificial grass protrude, wherein the spaces between the blades are filled with artificial granules. Artificial turfs are durable, but provide lower comfort of use as compared to natural turfs.
There are also known hybrid turfs, wherein a base mat with artificial grass is covered by soil, in which natural grass grows. Roots of the natural grass grow through the artificial base and integrate with it permanently. After some time, the natural grass blades grow above the level of the artificial grass blades, providing a comfort of use comparable to that of a natural turf. In the areas of heavy use, for example in the goal area on a soccer field, when the natural grass blades become damaged, the artificial grass blades are uncovered. The comfort of use in these areas is lowered, but not to such an extent as in case of damaged natural turfs.
Mats for hybrid turfs must provide appropriate parameters of the base, including permeability for water and air, they must also enable the natural grass roots to grow through the base. The easiest known way to provide appropriate base permeability is to perforate the base after it is installed on field—this, however, makes the installation of the base relatively complex.
One example of a hybrid turf is known from a US patent application US2007/0248773. It comprises a flexible support having a plurality of holes for allowing the drainage of water through the support. To the flexible support fibres are connected of artificial material in order to form a turf of artificial blades extending from the upper side of the support. The fibres are then kept substantially vertical by granular filling material, which can be made of rubber granules. The turf is therefore completed by living vegetable material put into the granular material by means of sowing, transplantation of portions of plants or a combination thereof. Finally, the living vegetable material in the form of seeds, or of portions of plants, is watered and dressed as known in the art. The turf can be easily carried, rolled up, turned over without spreading the granular material, and laid in a desired moment on a desired support surface for immediate use.
There are known methods for making artificial turf mats by weaving technology. For example, a European patent publication EP2142691 discloses an artificial grass mat comprising a ground fabric and a number of artificial grass blades protruding from the ground fabric, which form pile legs of the artificial grass burls, which are interlaced in the ground fabric over weft yarns in between, according to a W weave structure. The mat comprises at least 20,000 artificial grass burls per m2. Each burl comprises two pile legs, and each artificial grass burl between upright legs is interlaced three, five or seven times over weft yarns in between. At least one of the artificial grass blades protruding from the ground fabric is a monofilament yarn and at least one shrinkable textured yarn. The grass blade-forming pile-warp yarns have a linear mass of less than 5,000 dtex. The pile-warp yarns can be interlaced according to a ⅜W, 5/12W or 7/16W weave structure. The mat is made of polyolefins (polyethylene, polypropylene and blended forms) or polyamides. A mat of this type, supposed to be used as a mat for a 100% artificial turf, is characterized by a relatively high density and is not usable as a hybrid turf mat, because it does not provide adequate space for growth of natural grass. This results from the use of artificial grass blades of relatively low linear mass, below 5,000 dtex, as well as a high number of artificial grass burls—above 20,000 per m2.